/// <summary>
/// Test exception when trying to interpolate with only one point added.
/// </summary>
public void SplineExceptionOnOnlyOnePointAdded()
{
CubicSpline spline = new CubicSpline();
spline.AddDataPoint(1.0, new double[] { 1.0 });
//Assert.AreEqual(1, spline.Count);
//Assert.IsFalse(spline.CanInterpolate);
double[] y = spline.Interpolate(1.5);
}
/// <summary>
/// Test exception when trying to interpolate with only two points added.
/// </summary>
public void SplineExceptionOnOnlyTwoPointsAdded()
{
double[,] data = {{1.0, 1.0},
{2.0, 2.0}};
CubicSpline spline = new CubicSpline();
for (int i = 0; i < 2; i++)
{
spline.AddDataPoint(data[i, 0], new double[] { data[i, 1] });
}
//Assert.AreEqual(2, spline.Count);
//Assert.IsFalse(spline.CanInterpolate);
double[] y = spline.Interpolate(1.5);
}
/// <summary>
/// Test exception when trying to add points with the wrong dimension.
/// </summary>
public void SplineExceptionAddingWithDimensionMismatch()
{
CubicSpline spline = new CubicSpline(2);
//Assert.AreEqual(2, spline.Dimensions);
spline.AddDataPoint(1.0, new double[] { 1.0 });
}
/// <summary>
/// Test exception when trying to create spline with wrong dimension.
/// </summary>
public void SplineExceptionInvalidDimension()
{
CubicSpline spline = new CubicSpline(0);
}
/// <summary>
/// Interpolate points along a sine wave approximated with 12 points.
/// </summary>
public void SplineInterpolateSineWave()
{
int N = 12;
double[] x = new double[N];
double[] y = new double[N];
double xx = Math.PI;
double step = 4 * Math.PI / (N - 1);
for (int i = 0; i < N; ++i, xx += step)
{
double yy = Math.Sin(2 * xx) / xx;
x[i] = xx;
y[i] = yy;
}
CubicSpline spline = new CubicSpline();
for (int i = 0; i < N; i++)
{
spline.AddDataPoint(x[i], new double[] { y[i] });
}
//Assert.AreEqual(N, spline.Count);
//Assert.IsTrue(spline.CanInterpolate);
N = 30;
xx = Math.PI;
step = 3 * Math.PI / (N - 1);
for (int i = 0; i < N; ++i, xx += step)
{
double yExpected = Math.Sin(2 * xx) / xx;
double[] yCalculated = spline.Interpolate(xx);
//Assert.AreEqual(yExpected, yCalculated[0], 0.1);
}
}
/// <summary>
/// Test exception when trying to interpolate with no points added.
/// </summary>
public void SplineExceptionOnNoPointsAdded()
{
CubicSpline spline = new CubicSpline();
double[] y = spline.Interpolate(1.5);
}
/// <summary>
/// Interpolate between 4 points forming Z shape in two dimensions.
/// </summary>
public void SplineInterpolateFourPointShape2D()
{
double[,] data = {{1.0, 1.0, 2.0},
{2.0, 2.0, 4.0},
{3.0, 1.0, 2.0},
{4.0, 3.0, 6.0}};
CubicSpline spline = new CubicSpline(2);
//Assert.AreEqual(2, spline.Dimensions);
for (int i = 0; i < 4; i++)
{
spline.AddDataPoint(data[i, 0], new double[] { data[i, 1], data[i, 2] });
}
//Assert.AreEqual(4, spline.Count);
//Assert.IsTrue(spline.CanInterpolate);
double[] testinput = { 1.5, 2.5, 3.5, 3.9 };
double[] testoutput = { 1.6, 1.6, 2.0, 2.85 };
for (int i = 0; i < testinput.Length; i++)
{
double[] y = spline.Interpolate(testinput[i]);
//Assert.AreEqual(testoutput[i], y[0], 0.1);
//Assert.AreEqual(2 * testoutput[i], y[1], 0.2);
}
}
/// <summary>
/// Interpolate left and right of the 4 points forming a Z shape.
/// </summary>
public void SplineInterpolatePastEdgeOfFourPointShape()
{
double[,] data = {{1.0, 1.0},
{2.0, 2.0},
{3.0, 1.0},
{4.0, 2.0}};
CubicSpline spline = new CubicSpline();
for (int i = 0; i < 4; i++)
{
spline.AddDataPoint(data[i, 0], new double[] { data[i, 1] });
}
//Assert.AreEqual(4, spline.Count);
//Assert.IsTrue(spline.CanInterpolate);
double[] testinput = { 0.8, 0.9, 4.1, 4.2 };
double[] testoutput = { 0.8, 0.9, 2.1, 2.2 };
for (int i = 0; i < testinput.Length; i++)
{
double[] y = spline.Interpolate(testinput[i]);
//Assert.AreEqual(testoutput[i], y[0], 0.1);
}
}
/// <summary>
/// Validate that the data array can be cleared.
/// </summary>
public void SplineCanClearDataArrayThenAddAndInterpolate()
{
double[,] data = {{0.0, 0.0},
{1.0, 1.0},
{2.0, 2.0},
{3.0, 3.0},
};
CubicSpline spline = new CubicSpline();
// several tries
for (int t = 0; t < 3; t++)
{
for (int i = 0; i < 4; i++)
{
bool addResult = spline.AddDataPoint(data[i, 0], new double[] { data[i, 1] });
//Assert.IsTrue(addResult);
}
//Assert.AreEqual(4, spline.Count);
//Assert.IsTrue(spline.CanInterpolate);
// test interpolator
Random random = new Random();
for (int j = 0; j < 10; j++)
{
double x = random.NextDouble();
double[] y = spline.Interpolate(x);
//Assert.AreEqual(x, y[0]);
}
// test clear
spline.Clear();
//Assert.AreEqual(0, spline.Count);
//Assert.IsFalse(spline.CanInterpolate);
}
}
/// <summary>
/// Validate that adding duplicate x coordinates will reject the data.
/// </summary>
public void SplineRejectDuplicatePointsWhenAdding()
{
double[,] data = {{0.0, 0.0},
{1.0, 1.0},
{2.0, 2.0},
{3.0, 3.0},
};
CubicSpline spline = new CubicSpline();
for (int i = 0; i < 4; i++)
{
bool addResult = spline.AddDataPoint(data[i, 0], new double[] { data[i, 1] });
//Assert.IsTrue(addResult);
}
// try to add again
for (int i = 0; i < 4; i++)
{
bool addResult = spline.AddDataPoint(data[i, 0], new double[] { data[i, 1] });
//Assert.IsFalse(addResult);
}
//Assert.AreEqual(4, spline.Count);
//Assert.IsTrue(spline.CanInterpolate);
}
/// <summary>
/// Interpolate between 4 points forming a straight line.
/// </summary>
public void SplineInterpolateFourPointLine()
{
double[,] data = {{0.0, 0.0},
{1.0, 1.0},
{2.0, 2.0},
{3.0, 3.0}};
CubicSpline spline = new CubicSpline();
for (int i = 0; i < 4; i++)
{
spline.AddDataPoint(data[i, 0], new double[] { data[i, 1] });
}
//Assert.AreEqual(4, spline.Count);
//Assert.IsTrue(spline.CanInterpolate);
for (int i = 0; i <= 30; i++)
{
double x = 0.1 * (double)i;
double[] y = spline.Interpolate(x);
//Assert.AreEqual(x, y[0]);
}
}
/// <summary>
/// Test exception when trying to create spline with wrong dimension.
/// </summary>
public void SplineExceptionInvalidDimension()
{
CubicSpline spline = new CubicSpline(0);
}
/// <summary>
/// Test exception when trying to interpolate with no points added.
/// </summary>
public void SplineExceptionOnNoPointsAdded()
{
CubicSpline spline = new CubicSpline();
double[] y = spline.Interpolate(1.5);
}
